I'd argue that sister projects such as Wikidata, Wikiversity, etc, are greatly useful and that the solution to improving them is not to neglect them, but to provide more resources to them.
> I love Rosetta Code and we took a look at it. IIUC Rosetta Code does not allow to run the code, or to compose existing functions together to create new ones. Also, Rosetta Code's aims to have complete sets of implementations for their tasks, which is not our focus.